| 摘要 |
PURPOSE:To enable conversion to low impedance without detracting anything from sound quality by supplying electric current to a constant-voltage bias circuit by a constant-current circuit. CONSTITUTION:The bias electric power source supplying electric power to transistors 8 and 16 connected to single-ended push-pull SEPP is turned on by the constant-voltage circuit composed of transistors 7 and 11. Since electric current to be supplied to this constant-voltage circuit is supplied by the constant-current circuit composed of FETs 3 and 13, the SEPP circuit is enabled to operate by being supplied with the constant bias current. For this purpose, the input from terminals 1 and 2 is supplied to the middle point of the constant-voltage circuit and its voltage is shifted by the constant-voltage circuit and inputted to bases of transistors 8 and 16. Then, it is converted into low impedance from emitters of transistors 8 and 16 and outputted from terminals 18 and 19. |
